KR100962749B1 - Flexible printed circuit board - Google Patents

Flexible printed circuit board Download PDF

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Publication number
KR100962749B1
KR100962749B1 KR20070100261A KR20070100261A KR100962749B1 KR 100962749 B1 KR100962749 B1 KR 100962749B1 KR 20070100261 A KR20070100261 A KR 20070100261A KR 20070100261 A KR20070100261 A KR 20070100261A KR 100962749 B1 KR100962749 B1 KR 100962749B1
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KR
South Korea
Prior art keywords
flexible wiring
wiring board
layer
insulating base
conductive
Prior art date
Application number
KR20070100261A
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Korean (ko)
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KR20080031823A (en
Inventor
히데키 쿠사미츠
Original Assignee
야마이치덴키 가부시키가이샤
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Priority to JPJP-P-2006-00275324 priority Critical
Priority to JP2006275324A priority patent/JP4792368B2/en
Application filed by 야마이치덴키 가부시키가이샤 filed Critical 야마이치덴키 가부시키가이샤
Publication of KR20080031823A publication Critical patent/KR20080031823A/en
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Publication of KR100962749B1 publication Critical patent/KR100962749B1/en

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    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00Apparatus or processes for manufacturing printed circuits
    • H05K3/22Secondary treatment of printed circuits
    • H05K3/28Applying non-metallic protective coatings
    • H05K3/281Applying non-metallic protective coatings by means of a preformed insulating foil
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/0213Electrical arrangements not otherwise provided for
    • H05K1/0216Reduction of cross-talk, noise or electromagnetic interference
    • H05K1/0218Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/0213Electrical arrangements not otherwise provided for
    • H05K1/0237High frequency adaptations
    • H05K1/024Dielectric details, e.g. changing the dielectric material around a transmission line
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/03Use of materials for the substrate
    • H05K1/0393Flexible materials
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/01Dielectrics
    • H05K2201/0104Properties and characteristics in general
    • H05K2201/0116Porous, e.g. foam
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0275Fibers and reinforcement materials
    • H05K2201/029Woven fibrous reinforcement or textile
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/07Electric details
    • H05K2201/0707Shielding
    • H05K2201/0715Shielding provided by an outer layer of PCB

Abstract

An insulating base 34 having a plurality of conductive layers 36b covered with a protective layer 38 is surrounded by a mesh cloth member 32 to provide a flexible wiring board.
Figure R1020070100261
Flexible wiring board

Description

Flexible Wiring Boards {FLEXIBLE PRINTED CIRCUIT BOARD}

TECHNICAL FIELD This invention relates to the flexible wiring board which electrically connects electrical components.

In the electrical connection between the electrical equipment, for example, a flexible printed circuit board (FPC) as shown in Japanese Patent Laid-Open No. 2000-269612 is provided for practical use. Such a flexible wiring board 2 is, for example, as shown in FIG. 11A, a plurality of conductive layers 8a, 8b, and 8c covered with the protective layer 10 are formed of an insulating base 6. It becomes the structure formed on the surface of one side in.

The insulating base material 6 is shape | molded with glass epoxy resin etc., for example. The conductive layers 8a, 8b, and 8c are formed of, for example, a layer of copper alloy. The protective layer 10 is formed of, for example, a thermosetting resist layer or a polyimide film.

In addition, when the two conductive layers 8b become signal lines, the conductive layers 8a for ground lines are adjacent to both sides of each conductive layer 8b at predetermined intervals in order to reduce crosstalk in the signal lines. , 8c) are formed, respectively.

The ground layer (shield layer) 4 is formed in the whole of the other surface which opposes the surface mentioned above in the insulating base material 6. The ground layer 4 is connected to the above-mentioned conductive layers 8a and 8c through the via holes 6a and 6b. When the flexible wiring board is disposed in the metal body of the electronic device, the ground layer 4 is adapted to electrical interference with the metal body when a differential signal of a relatively high frequency band or the like is transmitted through the conductive layer 8b. It is provided to prevent transmission characteristic deterioration (confusion of impedance characteristic) caused.

Moreover, in a flexible wiring board, it may be difficult in manufacturing technique to employ | adopt the structure which forms the via holes 6a and 6b as mentioned above. In this case, the flexible wiring board 12 replaces the ground layer 4 with the outer surface of the dielectric layer 24 and the metal coating layer 14 having the metal coating layer 26 on the outer surface, as shown in FIG. 11B. The dielectric layer 16 also has a structure.

In FIG. 11B, the flexible wiring board has a structure in which a plurality of conductive layers 20a, 20b, and 20c covered with the protective layer 22 are formed on one surface of the insulating base 18. In addition, when the two conductive layers 20b are signal lines, the conductive layers 20a for the ground lines are adjacent to both sides of each conductive layer 20b at predetermined intervals to reduce crosstalk in the signal lines. , 20c) are formed, respectively. On the lower surface of the insulating base 18, a dielectric layer 16 having a metal coating layer 14 on its outer surface is laminated. On the other hand, the dielectric layer 24 which has the metal coating layer 26 on the outer surface is laminated | stacked on the upper surface of the protective layer 22 which opposes the insulating base 18. In addition, the metal cladding layer 14 and the metal cladding layer 26 are connected by the some through-hole which is not shown in figure so that mutual potential may be the same.

In this manner, the metal coating layer 14 and the metal coating layer 26 are each surrounded by the dielectric layer 16 and the dielectric layer 24 so as to surround each conductive layer 20b, resulting from electrical interference with the metal body. Deterioration of transmission characteristics (confusion of impedance characteristics) is prevented.

As shown in FIG. 11A, when the ground layer 4 is formed, impedance matching is necessary in a state where the thickness of the insulating base 6 is made relatively thin in order to secure the flexibility of the flexible wiring board. However, in order to achieve impedance matching, the conductor resistance increases because the width (wire diameter of the signal line) of each conductive layer 8b must be made thinner. For this reason, transmission loss increases and therefore, when the length of a flexible wiring board becomes comparatively long, there exists a possibility that the transmission of the signal of a high frequency band may become difficult.

In addition, as shown in FIG. 11B, the structure surrounding each conductive layer 20b with the dielectric layer 16 and the dielectric layer 24 interposed therebetween increases the effective relative dielectric constant and dielectric loss possessed by the dielectric. . In addition, as described above, the metal coating layer 14 and the metal coating layer 26 need to be connected by a plurality of through-holes not shown so that the potential of each other is the same, and thus the manufacturing process is increased. This increases manufacturing costs.

For this reason, as mentioned above, when a transmission loss increases and therefore the length of a flexible wiring board becomes comparatively long, there exists a possibility that the transmission of the signal of a high frequency band may become difficult.

In view of the above problems, the present invention is a flexible wiring board which electrically connects electrical components to each other. Even when the length of the flexible wiring board is relatively long, there is no fear that the transmission loss will increase, and the manufacturing cost will increase. It is an object of the present invention to provide a flexible wiring board that is free.

In order to achieve the object mentioned above, the flexible wiring board which concerns on this invention is an insulating base material which has a signal transmission conductive layer formed in at least one surface between a some grounding conductive layer and a grounding conductive layer, and a space | gap; It is made of a dielectric having a structure and is provided with a mesh-shaped covering member covering an insulating base material.

The flexible wiring board according to the present invention is made of an insulating base having at least one surface of a conductive layer for signal transmission formed between a plurality of grounding conductive layers and a grounding conductive layer, and a dielectric having voids. And a mesh covering member having an electrically conductive coating layer electrically connected to an end of the ground conductive layer on its outer circumferential surface and covering the insulating base material.

As is apparent from the above description, according to the flexible wiring board according to the present invention, since the electrical interference is reduced by covering the insulating base with a mesh covering member made of a dielectric having voids, the length of the flexible wiring board is relatively long. Even in this case, there is no fear that the transmission loss will increase, and the manufacturing cost will not increase.

1 and 2 show main parts of a first embodiment of a flexible wiring board according to the present invention, respectively.

In FIG. 1, the flexible wiring board 30 includes an insulating base 34, a protective layer 38, and a plurality of conductive layers 36a, 36b, and 36c covered with the protective layer 38 on one surface thereof. It is comprised including the mesh cloth member 32 as a mesh-shaped coating member which surrounds the whole insulating base material 34. In addition, in FIG. 1 and FIG. 2, a part of the flexible wiring board 30 which has a predetermined length is expanded and shown.

The insulating base material 34 is shape | molded by thickness of about 50 micrometers, for example with glass epoxy resin, a liquid crystal polymer, etc. In addition, the plurality of conductive layers 36a, 36b, and 36c are each formed in a layer of a copper alloy by a known pattern forming technique. The two conductive layers 36b become signal lines which are formed to extend in a direction perpendicular to the paper surface, substantially parallel to each other. The conductive layers 36a and 36c for the ground line are each formed at predetermined intervals adjacent to both sides of each conductive layer 36b in order to reduce crosstalk in the signal line. The width of each conductive layer 36b is set to about 350 µm, for example. The two pairs of conductive layers 36b are supplied with differential signals each having a communication speed of about 2.5 Gbps to 10 Gbps, for example. The protective layer 38 is formed of, for example, a thermosetting resist layer, a photoresist, a polyimide film, or the like.

The mesh cloth member 32 is made of dielectrics such as ethylene tetrafluoride, polyethylene, nylon and the like. The dielectric is not limited to these examples, and may be, for example, a dielectric having a specific coarseny of 1.01 to 4, inclusive. Here, only a gas such as air (relative dielectric constant: 1.00059) is not included as the dielectric. The relative dielectric constant becomes 4 or less because there is a possibility of deterioration of electrical characteristics when the dielectric constant exceeds 4.

The mesh cloth member 32 surrounds the protective layer 38 and the whole insulating base 34 at a predetermined uniform thickness. The thickness of the mesh cloth member 32 becomes 0.3 mm or more and 1 mm or less, for example. The porosity (opening ratio) of the mesh cloth member 32 is 50% or more, for example. The inner circumferential surface of the mesh cloth member 32 is in close contact with the outer circumferential surfaces of the protective layer 38 and the insulating base 34 without a bonding agent such as an adhesive.

The mesh cloth members 32 are disposed to face each other such that, for example, two mesh cloth members of a predetermined length sandwich the protective layer 38 and the insulating base 34, and end portions along the above-described signal lines are provided. (端 部) overlap each other and heat-sealed.

In addition, although the mesh cloth member 32 is formed by overlapping and heat-sealing the edge part mentioned above, it is not limited to this example, For example, as shown to B of FIG. 3, it is integrated in a cylindrical shape. The mesh cloth member 32 'may be formed. At that time, the clearance CL is formed between the inner circumferential surface of the mesh cloth member 32 'having a predetermined uniform thickness and the outer circumferential surface of the protective layer 38 and the insulating base 34. The thickness of the mesh cloth member 32 'becomes 0.3 mm or more and 1 mm or less, for example.

By using the mesh cloth members 32 and 32 'as described above, the through hole like the conventional flexible wiring board becomes unnecessary, so that the manufacturing process can be simplified and the manufacturing cost can be reduced.

FIG. 8 is used by the inventor of the present invention to verify the effect of the mesh cloth member 32 when a predetermined metal piece is disposed in close proximity to the flexible wiring board 30 of the first embodiment shown in FIG. 1. The result of the measurement of the characteristic impedance of the flexible wiring board 30 performed is shown.

In addition, the thickness of the mesh cloth member 32 of the flexible wiring board 30 provided for an experiment is set to 0.5 mm.

As a method of measuring characteristic impedance, the TDR (Time Domain Refletometry) method was used. The TDR method is performed by the measuring device 70 as shown in FIG. In Fig. 5, the measuring device 70 for measuring the characteristic impedance is, for example, a dedizing oscilloscope (11803B + SD24 manufactured by Techtronics). The dicing oscilloscope is comprised including the generator which sends a step pulse as a test signal to a to-be-measured object, and the sampler which detects the reflection waveform from a to-be-measured object.

The flexible wiring board 30 as an object to be measured is connected to the input / output part of the measuring device 70 through a connecting cable 72a. In this state, the termination of the flexible wiring board 30 is in an open state. Moreover, the flexible wiring board 30 is closely contacted and arrange | positioned on the copper strip | belt-shaped film.

In addition, there is a relationship represented by the following formulas (1) and (2) between the characteristic impedance Zr (?) And the reflectance?.

Zr = Zo (1 + ρ) / (1-ρ) (Ω)... (One)

ρ = reflection voltage / incident voltage = (Zr-Zo) / (Zr + Zo). (2)

However, Zo represents the known characteristic impedance (Ω) as a reference.

Therefore, the reflectance ρ is measured by the measuring device 70 described above, whereby the characteristic impedance Zr of the object to be measured is calculated from the equation (1). Moreover, the data which shows the characteristic line of the calculated characteristic impedance Zr is obtained from the output part of the measuring device 70 mentioned above, as shown to FIG.

FIG. 8 shows a characteristic line L3 representing the characteristic impedance of the flexible wiring board 30 by taking the impedance Ω on the vertical axis and the time t (ns) on the horizontal axis.

On the other hand, FIG. 6 shows the characteristic impedance of the flexible wiring board without the mesh cloth member 32 as the comparative example (A), taking the impedance Ω on the vertical axis and the time t (ns) on the horizontal axis. The line L1 is shown. The insulating base etc. which comprise a flexible wiring board become the same as the flexible wiring board 30. FIG. In addition, the measurement result shown in FIG. 6 shows that the flexible wiring board without the mesh cloth member 32 is mounted on the predetermined | prescribed test stand, without interposing the strip | belt-shaped film made of copper as mentioned above. It is obtained by connecting to the measuring device 70.

7 is a characteristic showing the characteristic impedance of the flexible wiring board without the mesh cloth member 32 as the comparative example (B) taking the impedance (Ω) on the vertical axis and the time (t) (ns) on the horizontal axis. The line L2 is shown. The insulating base etc. which comprise a flexible wiring board become the same as the flexible wiring board 30. FIG. In addition, the measurement result shown in FIG. 7 shows the measuring device 70 in a state in which the flexible wiring board without the mesh cloth member 32 is brought into close contact with the copper strip-like film as described above and placed on a predetermined inspection target. It is obtained by being connected to.

According to the above measurement results, as is clear from the characteristic line L1 shown in FIG. 6 and the characteristic line L2 shown in FIG. 7, the characteristic impedance of the flexible wiring board itself without the mesh cloth member 32 is , Approximately 112 (Ω), and on the other hand, when the flexible wiring board is in close contact with a copper band-like film, the characteristic impedance is about 80 (Ω), and the transmission characteristic of only that portion is disturbed. It was confirmed that this leads to an increase in losses.

In addition, as is clear from the characteristic line L1 shown in FIG. 6 and the characteristic line L2 shown in FIG. 8, the characteristic impedance of the flexible wiring board without the mesh cloth member 32 is about 112 (Ω). In addition, since the characteristic impedance of the flexible wiring board 30 also becomes about 112 (Ω), the characteristic impedance hardly changes, and the influence of the influence on the characteristic impedance of the copper strip-shaped film is increased. It was confirmed that it was prevented by the member 32.

Therefore, the electrical interference can be reduced by more than -30 dB (= 10 log 1/1000) as described later, so that the electrical interference prevention effect equivalent to the case where the ground plane is formed on the surface of the flexible wiring board opposite to the signal line formation surface Can be obtained.

For example, when the differential impedance of the conventional flexible wiring board shown in A of FIG. 11 becomes 100 (Ω), the signal line width of the signal line is about 100 µm, and the transmission loss has a frequency of 5 GHz. The transmission loss of the flexible wiring board 30 is about 8 dB / m in the signal of the frequency 5 GHz band while the signal in the band is about 13 dB / m, by the inventor of the present application. Therefore, the transmission loss is reduced by about 5 dB / m.

In addition, since the flexible wiring board 30 does not have the same ground layer as the conventional flexible wiring board, the design freedom of the characteristic impedance is improved. Therefore, the width or the like to the signal forming the signal line can be freely set. In addition, by selecting the width and spacing to the appropriate signal, transmission loss is reduced. Since the mesh cloth member 32 can be regarded as a mixture of air and a dielectric material, the effective relative dielectric constant is reduced when compared with only the dielectric material, and therefore the dielectric loss is also suppressed, so that transmission loss does not increase. Do not.

FIG. 10 shows the measurement result of the amount of mutual interference in the case where two flexible wiring boards by the inventors of the present application are brought into close contact with each other.

In Fig. 10, the mutual interference amount in the case where mutual interference amount (leakage power / transmission power) (dB) is taken on the vertical axis, frequency (GHz) is taken on the horizontal axis, and the two flexible wiring boards 30 are brought into close contact with each other. The characteristic line L5 which shows the change of the mutual interference amount according to the frequency of a signal, and the characteristic line L4 which shows the change of the mutual interference amount according to the frequency of the mutual interference amount in the comparative example (C) are shown.

The characteristic line L4 and the characteristic line L5 shown in FIG. 10 are each obtained by the vector network analyzer (henceforth a network analyzer) (The Agilent Technologies make: N5230A opt240), respectively. The measurement results obtained separately for the workpieces are displayed together in the same coordinate system. The network analyzer includes, for example, a signal source for transmitting a differential signal whose frequency can be changed, four output connectors connected to the object under test, and a directional coupler disposed between the signal source and the output connector. have. The measured object is connected to the output connector.

As the object to be measured, as shown in FIG. 9, two flexible wiring boards 30 having a length of 1100 mm are prepared, and the flexible wiring board 30 is in a state where the flat surfaces of the mesh cloth members 32 are in close contact with each other. Is supported. However, the mesh cloth member 32 is 475 micrometers in thickness, 52% of the porosity, 275 micrometers in diameter of nylon yarn, and 670 micrometers of eye opening which is a unit of the space | interval of a thread.

Two to-be-measured objects in the comparative example (C) become the flexible wiring board which does not have the mesh cloth member 32, and is prepared. The insulating base material of the flexible wiring board becomes the same as the flexible wiring board 30. The two flexible wiring boards are supported with each other in a state where the flat surfaces of the insulating base 34 adhere to each other.

As is apparent from the characteristic line L4 and the characteristic line L5 in FIG. 10, when the mesh cloth member 32 is present, electrical interference of about 30 dB is reduced as compared with the case where the mesh cloth member 32 is not present. It was confirmed by the inventor of this application.

3A shows the main part of the second embodiment of the flexible wiring board according to the present invention.

The flexible wiring board 40 shown in A of FIG. 3 is, in addition to the outer circumferential surface of the mesh cloth member 32 of the flexible wiring board 30 shown in FIG. 1, and has a metal coating layer 42A having a predetermined film thickness. And 42B) are formed.

In addition, in FIG. 3A, the same code | symbol is attached | subjected about the component which becomes the same in FIG. 1, and the duplication description is abbreviate | omitted.

The coating layers 42A and 42B made of metal are considered to have a skin effect by a copper tape having an adhesive on one side of a 10 μm thick copper foil, or an aluminum tape having an adhesive on one side of an 10 μm thick aluminum foil. Formed.

End portions along the extending direction of the ground conductive layers 36a and 36c in the coating layers 42A and 42B are connected to ends of the ground conductive layers 36a and 36c, which are not shown, respectively. In addition, even when the coating layers 42A and 42B are formed, it is confirmed by the inventor of this application that there is no change in the characteristic impedance and hardly a change in the transmission loss occurs. As a result, unnecessary radiation generated from the flexible wiring board 40 is reduced.

In addition, without being limited to these examples, a conductive woven material may be used in place of the metal coating layers 42A and 42B. In this case, flexibility can be improved as compared with the metal coating layer.

In addition, a radio wave absorption sheet may be used instead of the metal coating layers 42A and 42B. In such a case, the ends along the extending direction of the ground conductive layers 36a and 36c in the conductive absorbing sheet need not be connected to the ends of the ground conductive layers 36a and 36c not shown, respectively.

4 shows the main part of a third embodiment of a flexible wiring board according to the present invention.

In FIG. 4, the same code | symbol is attached | subjected about the component which becomes the same in the example shown in FIG. 1, and the duplication description is abbreviate | omitted.

In the example shown in FIG. 1, a plurality of conductive layers 36b are formed only on one surface of the insulating base 34, while in the example shown in FIG. 4, the insulating bases 54 face each other. A plurality of conductive layers 56b and 66b and the like are formed on one surface, respectively.

In FIG. 4, the flexible wiring board 50 has an insulating base material 54 having a plurality of conductive layers on surfaces facing each other, and a mesh shape surrounding the protective layers 58 and 68 and the whole insulating base material 54. The mesh cloth member 32 as a covering member is included.

On the surface of the Han group of the insulating base 54, a plurality of conductive layers 56a, 56b, 56c and 56d covered with the protective layer 58 are formed. On the other surface of the insulating base 54, a plurality of conductive layers 66a, 66b, 66c, 66d and 66e covered with the protective layer 58 are formed.

The insulating base material 54 is shape | molded by thickness of about 50 micrometers with glass epoxy resin etc., for example. In addition, the plurality of conductive layers 56a, 56b, 56c, 56d, 66a, 66b, 66c, 66d, and 66e are formed on the copper alloy layer by a known pattern forming technique. The pair of conductive layers 56b and 56d become signal lines which are formed so as to extend in a direction perpendicular to the ground in substantially parallel to each other. The conductive layers 56a and 56c for the ground line are formed at predetermined intervals adjacent to both sides of each conductive layer 56b for reducing crosstalk in the signal line, respectively. In addition, the pair of conductive layers 66d is a signal line formed so as to extend in a direction perpendicular to the ground substantially parallel to each other. The conductive layers 66b and 66c for ground lines are formed at predetermined intervals adjacent to both sides of each conductive layer 66d for reducing crosstalk in the signal lines, respectively.

The conductive layers 56b, 56d, and 66d are supplied with differential signals each having a communication speed of about 2.5 Gbps to 10 Gbps, for example. The protective layers 58 and 68 are each formed of a thermosetting resist layer or a polyimide film or the like, respectively.

Also in the present embodiment, the mesh cloth members 32 are disposed to face each other such that, for example, two mesh cloth members of a predetermined length sandwich the protective layers 58 and 68 and the insulating base 54, and are described above. The ends along one signal line overlap each other and are heat-sealed.

In addition, although the mesh cloth member 32 is formed by overlapping and heat-sealing the edge part mentioned above, it is not limited to this example, For example, as shown to B of FIG. 3, it is integrated in a cylindrical shape. The mesh cloth member 32 'may be formed.

Even in such a configuration, since the flexible wiring board 50 includes the mesh cloth member 32, the flexible wiring board 50 has the same effect as the first embodiment described above.

The present invention has been described with reference to the embodiments, but is not limited to the embodiments described above. The scope of the appended claims is to be construed broadly, including all modifications and equivalent structures and functions.

1 is a partial sectional view showing a main part of a first embodiment of a flexible wiring board according to the present invention.

FIG. 2 is a plan view showing a part of the example shown in FIG. 1. FIG.

Fig. 3A is a partial sectional view showing a main part of a second embodiment of a flexible wiring board according to the present invention, and Fig. 3B is a diagram showing a modification of the first embodiment of the flexible wiring board according to the present invention.

4 is a partial sectional view showing a main part of a third embodiment of a flexible wiring board according to the present invention.

Fig. 5 is a diagram schematically showing the configuration of a measuring instrument for measuring the characteristic impedance of a measurement object in the first embodiment of the flexible wiring board according to the present invention.

6 is a characteristic diagram showing a result of measuring characteristic impedance in Comparative Example (A).

7 is a characteristic diagram showing a result of measuring characteristic impedance in Comparative Example (B).

Fig. 8 is a characteristic diagram showing a measurement result of characteristic impedance in the first embodiment of the flexible wiring board according to the present invention.

Fig. 9 is a partial sectional view showing an object to be measured for the amount of mutual interference in the first embodiment of the flexible wiring board according to the present invention.

Fig. 10 is a characteristic diagram showing the characteristics of the amount of mutual interference in the first example and comparative example (C) of the flexible wiring board according to the present invention.

11A and 11B are partial cross-sectional views each illustrating a structure of a conventional flexible wiring board.

Claims (7)

  1. An insulating base material having at least one surface a conductive layer for signal transmission formed between a plurality of grounding conductive layers and the grounding conductive layer;
    Made of a dielectric having voids, and having a mesh-like covering member covering the insulating substrate,
    The mesh-shaped covering member is formed in a tubular shape with a predetermined gap with respect to the insulating base material.
  2. The method of claim 1,
    The mesh-shaped covering member is made of a dielectric having a relative dielectric constant of 2 or more and 4 or less.
  3. The method of claim 1,
    The thickness and porosity of the said mesh-shaped coating member are 0.3 mm or more and 1 mm or less and 50% or more, respectively, The flexible wiring board characterized by the above-mentioned.
  4. delete
  5. An insulating base material having at least one surface a conductive layer for signal transmission formed between a plurality of grounding conductive layers and the grounding conductive layer;
    Made of a dielectric having voids, and having a conductive covering layer electrically connected to an end of the grounding conductive layer on its outer circumferential surface and having a mesh-shaped covering member covering the insulating base material,
    The mesh-shaped covering member is formed in a tubular shape with a predetermined gap with respect to the insulating base material.
  6. The method of claim 5,
    The said conductive coating layer is a metal film or a conductive woven material, The flexible wiring board characterized by the above-mentioned.
  7. The method of claim 5,
    The said conductive coating layer is a radio wave absorber, The flexible wiring board characterized by the above-mentioned.
KR20070100261A 2006-10-06 2007-10-05 Flexible printed circuit board KR100962749B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JPJP-P-2006-00275324 2006-10-06
JP2006275324A JP4792368B2 (en) 2006-10-06 2006-10-06 Flexible wiring board

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KR20080031823A KR20080031823A (en) 2008-04-11
KR100962749B1 true KR100962749B1 (en) 2010-06-10

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US (1) US8014162B2 (en)
JP (1) JP4792368B2 (en)
KR (1) KR100962749B1 (en)
CN (1) CN101160018B (en)
SG (1) SG141415A1 (en)

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Publication number Priority date Publication date Assignee Title
JP2009177010A (en) * 2008-01-25 2009-08-06 Toshiba Corp Flexible printed circuit board and electronic apparatus
KR101249779B1 (en) * 2009-12-08 2013-04-03 엘지디스플레이 주식회사 Flexible Printed Circuit Board, Back Light Unit and Liquid Crystal Display Device Comprising That Flexible Printed Circuit Board
JP5904354B2 (en) * 2011-07-08 2016-04-13 住友電工プリントサーキット株式会社 Flexible printed wiring board with shield, manufacturing method thereof, and electronic device
WO2014021372A1 (en) * 2012-08-03 2014-02-06 株式会社村田製作所 Flat cable
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SG141415A1 (en) 2008-04-28
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US8014162B2 (en) 2011-09-06
JP2008098238A (en) 2008-04-24

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